Most members of the protozoan phylum Apicomplexa, which includes Plasmodium, have a restricted host range. One member is a notable exception. Toxoplasma gondii is able to infect virtually all warm-blooded animals and birds, and it is estimated that 1-2 billion people have been exposed to the parasite. This seminar will cover computational approaches that have been used to increase our understanding of Toxoplasma biology. Results from a recent effort that sequenced 62 strains representing isolates from around the world revealed aspects of population structure, new gene families, and genes under positive selection. Phenotypic differences between these diverse strains have also been described. For example, some strains are more virulent in mice than others. Genomic information in combination with the computationally based forward genetic approach of quantitative trait locus (QTL) analysis was critical in identifying genes responsible for this virulence phenotype.
Michael Behnke is currently an Assistant Professor in the Department of Pathobiological Sciences at the School of Veterinary Medicine, Louisiana State University, where he is studying the Apicomplexan parasite Toxoplasma gondii. The focus of his lab concerns developmental regulation by the parasite from the rapidly growing tachyzoite, to the slow growing bradyzoite cyst, through to the enteric/sexual stages. One area of research expands on work that determined the transcriptional profile of the merozoite stage, the first of the enteric stages the parasite develops into within the intestine of cats. The goal of this project is to develop a tissue culture platform using cat intestinal epithelial cells to provide the parasite the cell type in which it develops into enteric stages, and to use the information gleaned from profiling the merozoite stage to determine the effectiveness of differentiation in this system. Another project will utilize genetic crosses to investigate the transcriptional signatures that indicate differences in bradyzoite developmental competencies between strains to identify the basis of transcriptional control during the developmental process.
Department of Pathobiological Sciences at the School of Veterinary Medicine, Louisiana State University